[meteorite-list] NWA 3159 - Vesicular, plutonic eucrite with (pre-)terrestrial crystals?

From: bernd.pauli at paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: 13 Jan 2007 13:59:14 UT
Message-ID: <DIIE.000000C50000146B_at_paulinet.de>

Hello Greg, List, and Eucrite Buffs,

I recently bought Greg's last piece of NWA 3159, a 10.7-gram individual.
This is no.3 in my collection because there are already two breathtaking
cut slices clearly showing the two distinct lithologies:

1. the black, shock-melted, vesicular areas
2. the "normal" brecciated eucritic areas

I was wondering if I could also find the vesicular texture in an individual,
and, I did find such areas. But, then, I held my breath when I also spotted
a beautiful crystal aggregate of...maybe olivine or pyroxene under my micro-
scope at 16x and 32x magnification!

Yes, I know that olivine is not usually found in eucrites but it has been
found in small amounts in NWA 011, in Macibini, in NWA 049, in NWA 1000, etc.

I would like to invite those who have acquired such individuals from Greg and
who can examine their pieces under high(er) magnifications to closely examine
their specimens and maybe find such crystalline aggregates. Any input would
be greatly appreciated!

Mount Tazerzait and Baszk?wka have taught us that such crystals can survive the
meteorite's fiery descent through our atmosphere (if properly shielded). But
these crystals in my NWA 3159 individual are not really within the meteorite's
interior matrix but protrude from one of its vesicular cavities, in other words,
they may have been exposed to the atmospheric forces *IF* they should be pre-
terrestrial.

Would do you think? Terrestrial or pre-terrestrial (= meteoritic)? And what are they?
Quartz, pyroxene, olivine??? I will ask Jeff Kuyken, Mark Bostick, or Gary (or, maybe,
all of them ;-) to host the pictures I've taken so you can see what I am talking about.

Best eucritic and
crystalline wishes,

Bernd
Received on Sat 13 Jan 2007 08:59:14 AM PST